The Walking Dead isn’t generally known for fueling Reddit conspiracies, but one persistent thread weaves Breaking Bad into its pre-apocalypse world. Sunday’s Fear may even fuel that theory, dropping a Heisenberg easter egg that could blow this whole thing wide open.

What began as a network easter egg of The Walking Dead reusing Breaking Bad’s blue meth blossomed into an entire conspiracy theory that Glenn sold a Dodge Challenger to Walter White, and that Jesse Pinkman served as Daryl and Merle’s “janky little white guy” dealer. Netflix got in on the game to document the surprising overlap between the two series, and Sunday’s Fear The Walking Dead midseason premiere even added a verse.

The easter egg in question took place when Qaletaqa Walker (Michael Greyeyes) and Madison Clark (Kim Dickens) visited a Mexican bazaar in Sunday’s “The Diviner,” taking in the sights and sounds along the way. Breaking Bad fans might have recognized the tune playing on speakers throughout the market as that of “Negro y Azul,” a Heisenberg ballad performed in the Season 2 Breaking Bad episode of the same name:

I tried to be subtle with it. That was probably the moment when I fell the most deeply in love with Breaking Bad, when they did that cold open music video. As we were looking for pieces to incorporate into this world, it had the right vibe to it. It’s a gentle nod of admiration and adoration to Vince Gilligan.

If you’re really keen on stitching the two universes together, there are at least a few points for and against. The “Negro y Azul” song wasn’t necessarily implied to exist within the Breaking Bad world itself, though it’s worth remembering the episode aired in 2009. That would technically fit the timeline of The Walking Dead, as Sunday’s Fear double-premiere reiterated that the series takes place in 2010 (perhaps 2011), shortly after the original series premiered.

Zombie Heisenberg or no, Fear The Walking Dead Season 3 continues on Sundays, while The Walking Dead proper will return for Season 8 on October 22.